In-operation network planning

Optical Switching and Networking

Tornatore

Contreras

et al. 2017

Self Cite

Abstract-As current sustained traffic growth is expected to strain capacity of today's metro network, novel content distribution architectures where contents are placed closer to the users are being investigated. In that regard, telecom operators can deploy datacenters (DCs) in metro areas, thus reducing the impact of the traffic going from users to DCs. However, effective solutions to distribute contents to those metro DCs and to synchronize contents among them need to be investigated. In this paper, a hierarchical content distribution architecture for the telecom cloud is investigated: core DCs placed in geographically distributed locations, are interconnected through permanent "per content provider" (CP) virtual network topology (CP-VNT); additionally, metro DCs are placed close to users, and need also to be interconnected with the core DCs. CP's data is replicated in the core DCs through the CP-VNT, while metro-to-core (M2C) anycast connections are established periodically for metro DCs to synchronize contents. Since failures in the interconnection network might disconnect the CP-VNTs, in this paper recovery mechanisms are proposed to reconnect topologies and anycast connections. Topology creation, anycast provisioning and recovery problems are first formally stated and modelled as Integer Linear Programs (ILP). Solving these models, however, becomes impractical for realsized scenarios, so heuristic algorithms are also proposed. Exhaustive simulation results show that the investigated architecture provides significant improvements in both supported traffic and restorability compared to the case of a single core DC. Workflows to implement the algorithms within the Applications-based Network Operations (ABNO) architecture and extensions for PCEP are proposed. Finally, the architecture is experimentally validated in our ABNObased iONE test-bed.Keywords: Datacenter interconnection, Optical networks, Content distribution. INTRODUCTIONCloud-based contents are experiencing an exponential growth in users and data volume. In [1], Cisco forecast a yearly global growth of 23% in datacenter (DC)-to-user traffic, 29% in DC-to-DC traffic, and 22% in the intra-DC traffic. Likewise, Alcatel-Lucent highlights that metro traffic will increase 560% by 2017 mainly driven by IP video and cloud traffic [2], growing two times faster than core network traffic. They conclude that placing contents in DCs closer to users can result in a 41% bandwidth reduction in the metro networks. The resulting distributed DC architecture should come together with the extension of the core network functionalities towards the metro, as proposed in [3].Robust telecom infrastructures are needed to minimize the impact of failures on the services [4]; this is especially relevant in the case of video distribution. In fact, prolonged service outages and disruptions have negatively impacted the confidence of important companies toward cloud environments. Telecom operators are in a vantage position to capitalize on highly-reliable cloud services since they o...

Section: Cp-vnt_create Problemmentioning

confidence: 99%

mentioning

confidence: 99%

ABNO-driven content distribution in the telecom cloud

Optical Switching and Networking

Tornatore

Contreras

et al. 2017

Self Cite

“…n-operation network planning consists in making network resources available by reconfiguring and/or re-optimizing the network on demand and in real-time [1]. Although the concept of in-operation planning is general and can be applied to any network, in this work we focus on flexgrid-based optical core networks.…”

Section: Introductionmentioning

confidence: 99%

First Experimental Assessment of ABNO-Driven In-Operation Flexgrid Network Re-Optimization

Paolucci

Velasco

et al. 2015

J. Lightwave Technol.

Abstract-Traffic affected by link failures can be recovered using path restoration schemes. In dynamically operated networks provided with a control plane, restoration algorithms run in a centralized element, such as the Path Computation Element (PCE). To increase traffic restorability in flexgrid networks, multiple paths, sub-connections, can be used to restore every single affected connection. However, the multipath restoration scheme might result in a poor resource utilization entailing a lesser grade of service. In-operation network planning algorithms can be used to mitigate this problem once the failed link is repaired; we propose solving the so-called multipath after failure repair optimization problem (MP-AFRO) to reduce sub-connections count by aggregating those belonging to the same original connection and re-routing the resulting connection to release spectral resources. The MP-AFRO problem is modelled using a Mixed Integer Linear Program (MILP) formulation. In view of the complexity of the model and the limited time to solve the problem, we propose a heuristic algorithm that provides a good trade-off between complexity and optimality. The performance on the MP-AFRO heuristic is firstly validated by simulation. Next, the heuristic algorithm is deployed inside an in-operation planning tool in the form of back-end PCE (bPCE) inside the Application-based Network Operations (ABNO) architecture controlling a network; the bPCE is connected to the centralized active stateful PCE. MP-AFRO is experimentally demonstrated using a distributed field trial test-bed connecting the premises of Telefonica (Madrid), CNIT (Pisa), and UPC (Barcelona).

“…A specialized PCE can be used to perform complex computations, e.g. to perform inoperation planning [14], as demonstrated in [15], [16].…”

Section: Introductionmentioning

confidence: 99%

Experimental Assessment of ABNO-Driven Multicast Connectivity in Flexgrid Networks

Paolucci

Dios

et al. 2015

J. Lightwave Technol.

Self Cite

Abstract-The increasing demand of internet services is pushing cloud services providers to increase the capacity of their data centers (DC) and create DC federations, where two or more cloud providers interconnect their infrastructures. As a result of the huge capacity required for the inter-DC network, the flexgrid optical technology can be used. In such scenario, applications can run in DCs placed in geographically distant locations and hence, multicast-based communication services among their components are required. In this paper, we study two different approaches to provide multicast services in multi-layer scenarios assuming that the optical network is based on the flexgrid technology: i) establishing a point-to-multipoint optical connection (light-tree) for each multicast request, and ii) using a multi-purpose virtual network topology (VNT) to serve both unicast and multicast connectivity requests. When that VNT is not able to serve an incoming request as a result of lack of capacity, it is reconfigured to add more resources. A control plane architecture based on the Applications-based Network Operations (ABNO) one, currently being standardized by the IETF, is presented; workflows are proposed and PCEP extensions are studied for the considered approaches. The experimental validation is carried-out on a testbed set-up connecting Telefonica, CNIT, and UPC premises.